Rehabilitation With Stroboscopic Glasses Alters Force Steadiness And Accuracy In Chronic Ankle Instability Patients

Chronic ankle instability (CAI) patients have altered force steadiness and accuracy and increased visual reliance. However, little is known about the effect of using stroboscopic glasses on force steadiness and accuracy during rehabilitation in CAI patients. PURPOSE: To identify the effects of stroboscopic glasses on submaximal force steadiness and accuracy of ankle evertors, invertors, and hip abductors and visual reliance following 4 weeks of rehabilitation in CAI patients. METHODS: 50 CAI patients were equally assigned to 2 groups. The strobe group wore stroboscopic glasses during rehabilitation, while the control group did not. Before and after rehabilitation, force steadiness and accuracy were measured in 10% and 20% of maximum voluntary isometric contraction (MVIC) with eyes open (EO) and strobe vision (SV) conditions. Romberg ratios were calculated as SV/EO to identify visual reliance. Two-way ANOVA was used to identify differences in force steadiness and accuracy between groups and visual conditions. A mixed model ANOVA was used to identify differences in the Romberg ratio between groups and times. RESULTS: For force accuracy, the strobe group showed a greater pre-post difference in 10% of evertor MVIC than the control group when in the SV (0.36vs.0.23, p = 0.03) and showed a greater pre-post difference in 10% of evertor MVIC in the EO than in the SV (0.18vs.0.36, p = 0.04). In the force accuracy, CAI patients showed a lower Romberg ratio in 10% of evertor MVIC regardless of group after rehabilitation (1.48vs.1.13, p = 0.006), and the strobe group showed a lower Romberg ratio in 10% of evertors after rehabilitation (1.56vs.1.00, p = 0.03). CONCLUSIONS: CAI patients who wore stroboscopic glasses demonstrated increased force accuracy and had reduced visual reliance following 4 weeks of rehabilitation. In conclusion, stroboscopic glasses may offer clinicians a new means to reduce visual reliance and reweight sensory function during rehabilitation in CAI patients. - Table 1. Force Accuracy Condition (mean ± SD) Romberg ratio(mean ± SD) Variables Time Group EO SV SV/EO Evertors 10%*,**,†,‡ Pre Strobe 0.41 ± 0.20 0.60 ± 0.19 1.56 ± 1.03 Control 0.41 ± 0.22 0.54 ± 0.40 1.39 ± 1.44 Post Strobe 0.23 ± 0.12 0.24 ± 0.39 1.00 ± 0.29 Control 0.28 ± 0.17 0.31 ± 0.14 1.26 ± 0.71 20% Pre Strobe 0.63 ± 0.42 0.72 ± 0.43 1.41 ± 0.78 Control 0.73 ± 0.55 0.80 ± 0.67 1.07 ± 0.48 Post Strobe 0.42 ± 0.30 0.55 ± 0.55 1.53 ± 1.47 Control 0.47 ± 0.43 0.50 ± 0.35 1.13 ± 0.43 Invertors 10% Pre Strobe 0.68 ± 0.56 0.69 ± 0.57 1.18 ± 0.62 Control 0.76 ± 0.85 0.81 ± 0.85 1.39 ± 1.74 Post Strobe 0.29 ± 0.22 0.30 ± 0.21 1.04 ± 0.25 Control 0.33 ± 0.39 0.40 ± 0.50 1.05 ± 0.50 20% Pre Strobe 0.84 ± 0.57 0.90 ± 0.60 1.10 ± 0.33 Control 1.01 ± 0.95 1.06 ± 0.91 1.20 ± 0.63 Post Strobe 0.40 ± 0.20 0.42 ± 0.20 1.15 ± 0.34 Control 0.55 ± 0.67 0.54 ± 0.72 0.99 ± 0.22 Hip Abductors 10% Pre Strobe 4.68 ± 1.60 4.73 ± 1.33 1.06 ± 0.30 Control 5.19 ± 2.63 5.26 ± 2.25 1.11 ± 0.50 Post Strobe 5.86 ± 2.58 5.36 ± 2.57 0.90 ± 0.11 Control 6.11 ± 1.83 5.42 ± 1.59 0.90 ± 0.15 20% Pre Strobe 9.87 ± 2.89 12.75 ± 2.83 0.96 ± 0.08 Control 11.00 ± 4.36 10.64 ± 4.32 0.97 ± 0.08 Post Strobe 11.48 ± 4.52 11.19 ± 4.42 0.98 ± 0.07 Control 12.91 ± 3.28 12.39 ± 3.20 0.96 ± 0.08